Occlusion's Role in Periodontics

Occlusion In The
Practice of Periodontics
Dr Harshavardhan
Patwal

McNeil defines Occlusion as the
“Functional relationship between
components of the Masticatory system,
including the Teeth and the Supporting
tissues, Neuromuscular system,
Temporomandibular Joints and the
Craniofacial Skeleton.”

Ideal Occlusion (Dawson)
• Stable centric stops on all teeth when the
condyles are in the most superior and posterior
position
• An anterior guidance that is in harmony with
the border movements of the envelope of
function
• Disclusion of all posterior teeth in protrusive
movements
• Disclusion of all posterior teeth in non working
side
• Non interference of all posterior teeth on the

• Centric Relation: The position of the
mandible when the condyles are in an
orthopedically stable position
• Centric Occlusion: The position of the
mandible when there is maximum
interdigitation and occlusal contact between
maxillary and mandibular teeth

Differing Occlusal Schemes
• Theoretically Ideal Occlusion
• Canine Protected Occlusion
• Group Function Occlusion
• Physiologic / Non-Physiologic Occlusion
• Anterior Guidance Occlusion
• Mutually Protected Occlusion
• Balanced Occlusion

Questions that need
answers
• Is occlusion a risk factor for periodontitis
?
• What role does occlusion play in the
maintenance of a successfully osseo-
integrated dental implant?
• Do occlusal schemes differ between
natural dentitions and implant included
dentitions?
• Does increased occlusal force cause
Abfraction?

Trauma From Occlusion
• Trauma From Occlusion ( TFO ):
When occlusal forces exceed the adaptive
capacity of the periodontal tissues, the
resultant tissue injury is trauma from
occlusion

Synonyms for Trauma from
Occlusion
• Occlusal Trauma
• Periodontal Traumatism
• Occlusal Overload
• Traumatogenic Occlusion
• Traumatizing Occlusion

Classification of Trauma
from Occlusion
• Acute TFO : Results from an abrupt
increase in the amount of forces
• Chronic TFO : Results from gradual
changes in occlusion produced by tooth
wear, drifting movement, extrusion of
teeth, combined with parafunctional
habits such as Bruxism and Clenching

Classification of Chronic
Trauma from Occlusion
• Primary TFO : Periodontal Tissue
Injury resulting from excessive occlusal
forces applied to a tooth or teeth with
normal support.
• Secondary TFO : Periodontal tissue
injury resulting from normal or excessive
forces bing applied to tooth or teeth with
reduced support

Factors that determine
whether an Occlusion is
Traumatogenic
• Magnitude
• Direction
- Parallel to the Long Axis
- Lateral (Horizontal ) / Torque
• Duration
• Frequency
Criterion that determines if the occlusion is
traumatic is whether it produces periodontal injury,
not how it occludes.

Stages of Tissue Response
to Increased Occlusal
Forces
1) Injury
2) Repair
3) Adaptive Remodelling

Stage 1 - Injury
• Periodontal tissue injury occurs due to
increased occlusal forces
• Under forces of occlusion the tooth rotates
around a fulcrum, creating areas of pressure
and tension on opposing sides of the fulcrum
• Slightly excessive pressure stimulates bone
resorption
• Slightly excessive tension causes elongation of
PDL fibres and apposition of alveolar bone

Stage 1 Injury (cont’d)
• With greater Pressure, the compression of PDL
fibres produces areas of Hyalinization.Further
injury causes Necrosis of areas of PDL.
• Vascular changes, starting with vasostasis
within 30 minutes, which may eventually lead
to fragmentation of blood vessels in 1 – 7 days
• Associated with increased resorption of bone
(undermining resorption)
• Greater Tension leads to
thrombosis,hemorrhage, tearing of PDL and
resorption of alveolar bone.

Stage 2 - Repair
• The damaged tissues are removed and new
connective tissue cells, fibers, bone and
cementum are formed to restore the injured
periodontium
• Forces are traumatic only as long as the
damage exceeds the reparative capacity.
• Buttressing bone formation

Stage 3 – Adaptive
Remodelling
• If the repair process cannot keep pace with the
destruction caused by the Occlusion, the
periodontium is remodeled in an effort to
create a structural relationship in which forces
are no longer injurious to the tissues
• This results in a thickened periodontal
ligament which is funnel shaped at the crest
and angular defects in the bone with no pocket
formation

Role of occlusion in
Periodontal Disease –
Historical review
• Karolyi Effect ( 1901 )
• Stillman’s definition of TFO ( 1917 )
• Stones and Box – Experiments on sheep and
monkeys ( 1938 )
• Orban ( 1939 ) – Based on autopsy and animal
experiments described changes occurring to teeth
when excessive forces were applied – describing
changes that occur to sides with tension and sides
with pressure.

Shortcomings of Early
Studies
• These early studies had the following
shortcomings
• They were primarily based on individual
observations and opinions
• They lacked proper controls
• The design of these studies did not justify the
conclusions drawn

Glickman’s Co-Destructive
Effect

Glickman’s Co-destructive
Effect

Alteration of Pathway of
Inflammation
- Glickman

Formation of Infrabony
Pocket
- Glickman

Glickman’s Hypothesis
• TFO may alter the pathway of inflammation to
the underlying tissues.
• Inflammation may then proceed to the
periodontal ligament rather than to the bone.
• Resulting bone loss would then be angular and
pockets could be intrabony

Glickman’s Conclusions
• Trauma from occlusion is an integral part of
the disease periodontitis rather than an
unrelated disease entity and is an etiologic
factor in the formation of infra bony pockets
and angular or crater like osseous defects.
• Considered TFO a Co-Destructive factor in the
etiology of periodontal disease
• Occlusal Adjustment is to be considered as
inherent part of periodontal therapy

Waerhaug’s Plaque Front
Hypothesis
• Measured the distance between subgingival
plaque and the periphery of associated
inflammatory cell infiltrate and the surface of
the adjacent alveolar bone.
• He suggested that angular bony defects and
Infrabony pockets occur when the sub gingival
plaque of one tooth reaches a more apical level
than plaque on an adjacent tooth

Waerhaug’s Plaque Front
Hypothesis
• Connective tissue attachment and resorption of
alveolar bone around teeth was exclusively the
result of inflammation associated with plaque.
• Angular defects result due to the difference in
the apical migration of plaque.

Problems with Early studies
Initial studies introduced forces that
were continuous or intermittent that
were in one direction
Created Orthodontic type of forces
Also lot of the early studies were on
autopsy specimens
Did not create Jiggling trauma that is
seen when TFO is present in human

Studies with Orthodontic
Forces
• Studies by Steiner (1981) and Wennstrom
(1987) however demonstrated that
orthodontic forces producing bodily or
tipping movement of teeth may result in
Gingival Recession with loss of connective
tissue attachment
• This occurred at sites with gingivitis, and
when in addition the tooth was moved
through the alveolar proceess.

Animal Experiments-Jiggling
Trauma
Rochester Group
• Used squirrel monkeys
• Trauma induced by repetitive interdental
wedging
• Mild to Moderate gingival inflammation
was introduced
• Experiments were carried on upto 10
weeks

Animal Experiments-Jiggling
Trauma
Univ. of Gothenburg Group
• Used Beagle dogs
• Produced jiggling trauma by placing cap
splints and orthodontic appliances
• Induced severe gingival inflammation
• Experimental times were upto one year

Jiggling Trauma – Healthy
Periodontium

Jiggling Trauma – Healthy
but Reduced Periodontium

Jiggling Trauma superimposed
on teeth with Suprabony
Pockets

on teeth with Infrabony
Pockets

Conclusions of Experiments
on Teeth with Experimental
Periodontitis
• The Rochester Group concluded that
Trauma superimposed on teeth with
Suprabony or Infrabony Pockets
a) Caused increased loss of alveolar bone
b) Failed to produce additional loss of
connective tissue attachment

Photomicrograph of teeth with
and without Jiggling Trauma
superimposed on teeth with
Infrabony Pockets

Jiggling Trauma superimposed on
Teeth with Experimental
Periodontitis-Gothenburg Group -
Conclusions
• TFO that allows adaptive alterations to
develop in pressure/tension zones of the
periodontal ligament will not aggravate a
plaque associated periodontal disease
• In TFO were adaptation did not occur the
Zone of Co-Destruction merged with the
Zone of Irritation resulting in apical
migration of the dento-gingival epithelium
and Aggravation of Periodontal Disease

Animal studies – Yoshinaga 2007
Distribution of RANKL in rat periodontium
during Lipopolysaccharide induced
inflammation with and without Occlusal
Trauma

Yoshinaga 2007
• Lipopolysaccharide(LPS) was injected rat
gingiva to induce inflammation. Occlusal
trauma was introduced by the placement of
gold inlays.
• The study found significantly more RANKL+ve
cells in the LPS and in the LPS + trauma
groups
• There was significantly more RANKL+ve cells
in the LPS + trauma group than the other two

Yoshinaga 2007
• This report demonstrated that LPS induced
inflammatory bone resorption with traumatic
occlusion, is more than destruction induced by
LPS or traumatic occlusion alone.
• The study also hinted that occlusal trauma
influenced the spread of LPS induced
inflammation to the furcation region .

Stress induced regulation of
mRNA Expression of
Osteoprotegerin
• Tsuji in 2004 reported that the combination
of LPS and mechanical stress reduced the
expression of Osteoprotegerin in
periodontal ligament cells in vitro
• These studies seem to indicate that occlusal
stress in association with LPS induced
inflammation upregulates factors that
promote increased bone resorption

Clinical Studies - Ethical
Issues
• Problems associated with non treatment of
Diagnosed Periodontal Diseases
• Therefore difficulties in formatting a RCT
World Workshop of Periodontics 1996 recognized
that “ Prospective studies on the effects of occlusal
forces on progression of periodontitis are not
ethically acceptable”
Therefore most studies in humans have been
Descriptive or Retrospective

Meta analysis
Systematic reviews
In vitro
research
Animal research
Ideas, editorials, opinions
Case reports
Case control studies
LEVELS OF CLINICAL EVIDENCE
Randomized
controlled trials
Cohort studies
1
2
3
4
5

Clinical Trials – Philstrom
1986
• Studied the association between TFO and
Periodontitis by assessing a series of clinical and
radiographic features of Maxillary 1st molars
• They concluded that teeth with increased
mobility and widened periodontal ligament
space had in fact, deeper pockets, moe
attachment loss and less bone support than
teeth without these symptoms

Clinical Trials – Burgett
1992
• Studied the effect of Occlusal Adjustment in
treatment of Periodontitis
• 50 patients following examination at baseline
were treated with Root Debridement and Flap
Surgery, out of whom 22 received
Comprehensive Occlusal Therapy.
• On re-examination those with Occlusal
Therapy had on average 0.5 mm greater
Attachment Gain than those who did not
receive occlusal therapy

Effects of Occlusal Discrepancies
on the Progression of Periodontal
Disease
• Nunn and Harrel in a series of studies published
in 2001 and 2004 reported that two specifically
defined occlusal parameters consisting of either
an occlusal discrepancy between centric
relation occlusion and centric occlusion and/or
a non working side contact.
• These studies reported that these occlusal
discrepancies are an independent risk factor
for the progression of periodontal disease with
periodontal treatment resulting in improved

Association of Occlusal Contacts
with Pocket Depths –Nunn &
Harrel 2009
• The following associations of deeper pocket depth
with occlusal prematurity was noted
• In CRO (0.89mm, p < 0.0001)
• Post. Protrusive contact( 0.51mm,p<0.0001)
• Balancing contacts ( 1.01mm,p<0.0001)
• Combining balancing &working side contacts
(1.13mm,p<0.0001)

Nunn & Harrel 2009
• Multiple types of Occlusal prematurities were
shown to be associated with deeper probing
pocket depths and an increased assignment of
a less than “Good” prognosis
• They suggested that treatment of Occlusal
Discrepancies as a routine part of periodontal
treatment may be indicated

Contradicting Studies
• Rosling et al (1976) – Infrabony pockets
associated with hypermobile teeth exhibited the
same degree of healing as adjacent firm teeth
• Jin and Cao (1992) – Concluded that there were
no significant differences in probing depth,
clinical attachment levels or alveolar bone
height, when comparing teeth with and without
abnormal occlusal contacts

Contradicting Studies
• Bernhardt et al (2006) investigated the potential
associations between dynamic occlusal
interferences and signs of periodontal disease
in posterior teeth
• They demonstrated a weak relationship
between non working side contacts and
increased probing depth and attachment loss.

What do we Know?
• Trauma from occlusion does not initiate
gingivitis or periodontitis
Literature review though not unambiguous
seems to suggest the following:
• Occlusion may be a risk factor in the
progression of periodontal disease
• Healing following surgical treatment of
periodontal disease may be more advantageous
in Non-mobile Teeth than in Mobile teeth

Evidence Based Approach for
Decision
Making
Newman et al : Ann Periodontol 2003
• Is Objective
• Is Scientifically Sound
• Is Patient Focussed
• Incorporates Clinical Experience
• Is Thorough and Comprehensive
• Uses Transparent Methodology

Role Of Occlusion In
Implant Dentistry

Occlusal Considerations –
Implant Dentistry
• Main difference between a tooth and implant is the
lack of Periodontal Ligament
• There are no proprioceptive nerve endings
• The Blood Supply is less
• Implants have very limited capacity to displace
axially ( 3 – 5 µm)

Consequences of Biomechanical
Overload
• Early Implant Failure
• Early Crestal Bone Loss
• Intermediate - Late bone loss & implant failure
• Screw loosening/Un-cementation
• Component/Porcelain Fracture
• Peri Implantitis (from crestal bone loss)

Implant Protective
Occlusion
• No premature occlusal contacts/inteferences
• Influence of Surface Area
• Mutually Protected Occlusion
• Implant body angle to occlusal load
• Cusp angle to crown
• Cantilever – Horizontal/vertical Offset
• Implant Crown Contour
• Protect the weakest component

Proprioception in
Implants
• Teeth identify inteferences at approximately
20µm.
• An implant opposing a natural tooth detects an
interferences at 48µm
• An implant opposing an implant detects an
interference at 64µm
• When a tooth opposes an implant supported
overdenture the awareness is at 108µm

Occlusion on Natural Teeth
and Implants

Occlusion on Natural Teeth
and Implants
Implants do not display Immediate Horizontal Mobility. With Heavier
Forces mobility ranges from 10 to 50µm.

Axis Of Implant To The
Load
• Non – Axial / Off Axis loading is harmful
• Cantilevered Loading is harmful
• Control the Horizontal Force with Cusp
Incline
• Reduce the area of the Occlusal Table

Occlusion and Abfraction
• Abfraction – Coined from two Latin words
Ab – Away
Fractio – Breaking
ie. Breaking Away
Term coined by John Grippo in 1991

Abfraction
• Definition: The Pathological loss of tooth
substance caused by Biomechanical
Loading Forces that result in flexure and
failure of enamel and dentine at a
location away from Loading

Abfraction - History
• In the early ‘80s McCoy questioned the role of
tooth brush abrasion in what had previously
been considered cervical abrasion
• He postulated using Engineering Studies that
tensile stress from mastication and
malocclusion broke the Hydroxyapatite
chemical bonds making them susceptible to
toothbrush abrasion and chemical erosion

Tooth Flexure Model – Tensile
strsses concentrated at Cervical
areas

Abfraction with Gingival
recession

Treatment of Abfraction
• Education
• Occlusal Equilibration
• Guard/Splint Therapy

•There is a tendency to think of occlusal
adjustment
solely in a negative sense.
•Equally important purpose is to provide
Functional
•Stimulation necessary for the preservation of
Periodontal Health.

Relationship between Occlusal
Force and progression of
Periodontal Disease – Takeuchi
2010
• Prognosis of teeth in maintenance phase was
significantly affected by Low Occlusal Forces ( p
< 0.006)
• Suggested that Low Occlusal Forces might be
possible Risk Factor for Periodontal Disease
Progression

Biologic Basis of Occlusal
Function
• Physiologic Occlusion is present when no signs
of Dysfunction or Disease are present and no
treatment is indicated
• Non-Physiologic Occlusion is associated with
Dysfuction or disease due to tissue injury
Criterion that decide whether the occlusion is
traumatic is whether it produces periodontal
tissue injury, not how the teeth occlude

Terminologies
• Intercuspal Position
• Muscular Contact Position
• Excursive Movement
• Laterotrusive Side
• Mediotrusive Side
• Protrusion
• Retruded Position
• Guidance
• Interference

Guidelines for Therapeutic
Occlusion
Natural Dentition
1. ICP –
2. RCP –
3. Vertical Stops – Stable multiple contacts on the
posterior teeth providing individual tooth stability.
No buccal – lingual thrust or impact to any tooth in
closure to ICP.
4. Laterotrusive Excursions – Smooth movement with
diclusion controlled by canine and first premolar
on thelaterotrusive side .No contacts on

Guidelinesfor
TherapeuticOcclusion
Natural Dentition – Cont’d
5. Protrusive Excursions – Smooth movements with
multiple contacts bilaterally distributed on the
anterior teeth
6. Interfernces – Freedom from non working side
contacts. Freedom from posterior contacts on
protrusive excursions. Freedom from single
tooth molar contacts on any excursion.
7. Acceptable free way space – The normal range is
1-4mm . If the free way space measures more
and there are symptoms it must be treated

Guidelines for Occlusion in
Dental Treatment
Subjective to response to occlusion
• Lack of unpleasntness or untoward
awarness concerning in dental occlusion.
• Acceptable
- Freeway space
- Speech articulation
- Chewing ability
- Mandibular position

Recommended Materials for
Identifying and Making Tooth
Contact and Contact Movement
Products
• Occlusal registration strips
• Occlusal wax indicator
• Marking ribbion ,red,green
• Articulating paper, Blue

Correction of Retrusive
Prematurities
MUDL Rule
• Grooving
• Spheroiding
• Pointing

Occlusal Adjustment
Grooving
• Entails restoring the depth of devolopmental
grooves ; Done with tapered cutting tool until
its desired depth is attained.

Occlusal Adjustment
Spheroiding
• Consists of reducing the supracontact while
restoring the original tooth contour;Effort made
to preserve the occlusal height of the cusps.

Occlusal Adjustment
Pointing
• Consists of restoring cusp point contours
; Done by reshaping the tooth with
rotating cutting tools.

Schedule of Coronoplasty
1. Remove retrusive prematurities and eleminate
the deflective shift from RCP to ICP.
2. Adjust ICP to achieve stable ,simultaneous,
multipointed, widely distributed contacts.
3. Test for excessive contact (fremitus) on the
incisor teeth.
4 Remove posterior protrusive supracontacts and
establish contacts that are bilaterally
distributed on the anterior teeth.

Schedule of Coronoplasty
5. Remove or lessen mediotrusive interferences.
6. Reduce excessive cusp steepness on the
laterotrusive contacts.
7. Eliminate gross occlusal disharmonies.
8. Recheck tooth contact relationships.
9. Polish all rough tooth surfaces.

Identifying Retrusive
Prematurities –MUDL Rule

Group Function Guidance
• Most favorable alternative to canine
guidance
• Several teeth on the working side contact
during laterotrusive movement
• Most desirable consists of the canine,
premolars and sometimes mesio – buccal
cusp of first premolar

Mutually Protected
Occlusion
• A mutually protected occlusion is an
occlusal scheme in which the anterior
teeth protect the posterior teeth, and vice
versa.
• Anterior guidance of an implant should
be as shallow as practical
• On lateral excursions the posterior teeth
are discluded by anterior segment of jaws

Forces on Implants need to
be Axially Directed

Maxillary Stabilization
Appliance
• Remains the most universal and effective long
term means of interfering with the effects of
bruxism.
• Aim of the appliance is to protect the tooth
surface and dissipate forces built up in the
mucoskeletal system through bruxism.
• Appliance results in an immediate reduction of
masseter and temporalis muscle activity levels.

Criteria for Maxillary
Stabilization Appliance
Occlusal Criteria
• Appliance : stable
• RCP,ICP : stable ,multipointed , widely
distributed contacts.
• ICP: Posterior vertical steps in firm
contact;incisor teeth in slight infracontact.
• RCP-ICP relationship : in the same sagittal
plane.
• Smooth gliding contact in all excursions.
• MCP : stable , repeatable.

Conclusions
• There is no scientific evidence to show that trauma
from occlusion causes gingivitis or periodontitis or
accelerates the progression of gingivitis to
periodontitis.
• The periodontal ligament physiologically adapts to
increased occlusal loading by resorption of the
alveolar crestal bone resulting in increased tooth
mobility. This is Trauma from Occlusion and is
reversible if the Occlusal force is reduced.

Conclusions
• Trauma from Occlusion may be a co-factor which
can increase the rate of progression of an existing
periodontal disease.
• There is a place for Occlusal therapy in the
management of periodontitis,
• Occlusal therapy is not a substitute for
conventional methods of resolving plaque-induced
inflammation.

Conclusions
• A Comprehensive Knowledge of the
Dynamics of Occlusal Loading Forces on
Peri-Implant tissues is the most significant
factor in the successful rehablitation of
patients with Implants

Occlusion's Role in Periodontics

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